This invention generally relates to a color image processing apparatus capable of being preferably applied to a simple electrophotographic color copying machine in order to obtain satisfactory color image.
The color image processing apparatus optically reads color image information on a document, separates the information into multiple colors including black, red and blue, and record the color image on a recording paper through its electro-photographic color copying machine on the basis of above separated color images. This type of color image processing apparatus is disclosed in Japanese Patent Publication Open to Public Inspection Nos. 147374/82 and 62769/83.
FIG. 67 shows part of a key assembly of the said color image processing apparatus.
In this figure, color image information is separated into white and cyan colors, each of which is projected onto image sensors 104 and 105 for electrophotographic conversion.
More specifically, white and cyan color signals are supplied to the subtracter 2 where red color is separated. These white, cyan and red colors are gain-controlled by the AGC circuits 3, 4 and 5, respectively, and then are coded by the binary coding circuits 6, 7 and 8, respectively. The coded output is again converted into red and black color signals by the arithmetic circuit 9, for example, and these signals are supplied to the color copying machine as image signals for color reproduction of the original. Further, in Japanese Patent Application O.P.I. No. 89371/1982 is disclosed a method of detecting the region designated with a color marker on a black-white document.
There are two possible methods for image processing operations (including resolution control, enlargement and reduction) of electrophotographically converted images by use of a color image processing apparatus that can produce color image. One method is intended for analog image data which has not been color-separated, as shown in FIG. 68; the other for coded image data, as shown in FIG. 69.
One problem of the format method lies in a large circuit scale attributable to that the method uses the image processing means 10 for each of multiple color-separated signals for image processing. Another problem lies in that analog signals prevent smooth image processing.
The latter method has also problems. One problem is attributable to digitized digital signals which the method is to handle. This enables easier signal handling than the former method, but restricts the scope of image processing to enlargement and reduction. As a result, there is a restriction in correction of resolution because of a smaller amount of information.
When designating a region on a document with a color marker or the like, and subjecting inside or outside the designated area to image processing such as color conversion based on the detected color marking, the document possibly treated with such an apparatus is essentially a black-monochromatic (white/black) document; the apparatus is incapable not only of detecting color marking on a multi-color document (color document) but also of performing the above-mentioned image processing.